Hypodermic syringe



arch M, 1939 L. A. DUNAJEFF HYFODERMIC SYRINGE Filed oop. 29, 1957 BY 9%www ATTORNEY Pate-@ame r4, -I

' UNITED srA'rss P 'aisance AT1-:Nr OFFICE My invention relates tohypodermic syringes and has particular reference to syringes used forinjecting medicinal liquids into living tissues.

` Hypodermic syringes usually employ very fine 5 needles havingrelatively high resistance to the' flow of liquids so that it takes along time to ll a syringe with a liquid, during which time the -plungermust be slowly Withdrawn from the cyl-- inder, requiring constantattention of the operator so as to iill the syringe with a desiredquantity of the liquid. My invention has for its object therefore toreplace the manual labor of iilling the syringe by an automaticoperation. For this purpose I provide a spring mounted on the outside l5ofthe syringe cylinder and having manually operable clamps for settingthe spring at a desired point on the cylinder under proper compressionand subsequently releasing the other end of the "spring for engagementwith the plunger so as to cause the latter to be withdrawn from thecylinder by the spring.

The ordinary manual process of injecting liquids into living tissuesalso has considerable disadvantages in that the hands, While engaged in.

forcing the plunger into the cylinder, 4cannot remain perfectly steadywith a result that the point of the needles moves in the tissue, causingpain and being liable to break 01T. Another object of my invention istherefore to provide an automatic means for forcing;v the plunger intothe cylinder after vthe latter has been filled with the liquid therebyrelieving the operators hands from the Work of manipulating the plungerand therefore enabling him to hold the syringe steadily in a desiredposition.

For this purpose I use the same spring which is provided for withdrawingthe plunger from the cylinder. The spring has an outer shell extendingfrom its end nearest the needle, which for convenience may be calledfront end, to the rear end of the plunger. The front end of thespring'is attached to the shell and is provided with a clamp forengaging thecylinder, the'rear end engages a sliding sleeve with a clampwhich may be set to engage the end of the cylinder or the plunger. Inthe latter case the spring will force the plunger out of the cylinder aswas explained for the syringe filling operation. By'- clamping thesleeve on lthe end of the cylinder, however, the spring through thetubular shell will pull the plunger in the cylinder if the clamp on thefront end of the spring is released. It is only necessary for theoperator to hold the syringe steadily with the clamp released in orderto inject the liquid into the tissues. The operation can be stopped atany time by releasing the clamp handle or retarded by partiallyreleasing the clamp handle* and using the clamp as a brake.

Another object of my invention is toprovide anl adjustable guide at theend of the needle for. I limiting the depth of its insertion in thetissues.

My invention is more fullyy described in the accompanying specificationand drawing in` which- Fig. 1 is a view of my syringe partly in sectionl l. -and in its inoperative position with the plunger in the cylinder.

Fig. 2 is an outside View of the syringe with the spring set foroperation and the sleeve set for withdrawing the piston from theplunger.

Fig. 3 is an' outside view o-f the syringe with the spring expanded uponcompletion of the liquid drawing operation.

Fig. 4 is a detail View of the sliding sleeve.

Fig. 5 is a sectional view taken on the line 20 5-5 of Fig. l.

Fig. 6 is a sectional view taken on the line 8 6 of Fig. 1.

Fig. '7 is a detail View of a locking and braking device for the upperend of the spring. 25

My syringe consists of a cylinder l with a. closed l front end 2 havinga tapering extension 3 for a needle 4 which iits frictionally on theextension. The extension 3 has a threaded tubular portion 5 on which isthreaded a collar 6 with lugs 'I con- 30 verging on the needle. The endsof the lugs form a guide for limiting the depth of insertion of theneedle into living tissues for injection. 'Ihe length of the needlebeyond the guide may be regulated for the desired depth of the insertion35 by screwing the collar on the portion 5 to a i desired depth. Thecylinder I has a shoulder or rim 8 on the open rear end. A piston orplunger 9 slidably fits in the cylinder and has a shoulder or ange l ton the rear end. The front closed 4u end has an aperture insideregistering with the central aperture in the needle.

It may be noted that the described parts form an ordinary hypodermicsyringe. In fact, my device can be used with any suitable syringe pro-.45 vided it has enlarged portions 8 and i0, and if the front end 'canbe provided vwith the portion 5, although the latter may be omitted ifdesired. The syringe cylinder may be made of any suitable A materialsuch as glass, composition or metal'. 5o

Needles of diierent sizes can be used and they can be removed andreplaced without removing the guide member formed of the collar B withthe lugs i.

A tubular casing VH is placed over the cylinder 55 I and is threaded onthe rear end for a cap I2. The front end is closed over the cylinder andhas openings I3 for handles I4 extending from a clamping ring I5. Thelatter is made of tempered steel and is twisted as shown in detail inFigs. 6 and 'I so that it 'clamps the cylinder but can be released bysqueezing the handles I4 between the operators fingers. A helicalcompression spring I6 is placed on the cylinder inside the casing I Iand rests against the clamping ring I5. The rear end of the spring restsagainst the front anged end of a sleeve I1`sliding in the casing II. Therear end of the sleeve has a flange I8 resting against the inner side ofthe ange I0. The spring is made so that it remains under tension whenfully extending to the front of the syringe cylinder I as shown inFig. 1. The sleeve I1 has punched out portions I9 bent inwardly andprovided with hooks 20 on the ends engaging the inner or front shoulderof the rim 8. The inner diameter of the anges on the sleeve i1 isslightly larger than the diameter of the rim 8 so that the sleeve I1 canbe moved on either side of the rim. The diameter of the iiange I0 is,however, larger than the diameter of the rim 8 so that the sleeve I1bears against the front shoulder of the ilange I0 by the ilange IB. Thesleeve is made of a resilient metal such was tempered steel so that thelugs I9 can be deflected away from the rim 3 by pressing on handles 2Iextending from the lugs I9 through longitudinal slots 22 in the casingil. The sleeve has also handles 23 extending through the slots 2x2 fromthe solid portion of the collar. The collar is therefore released fromthe rim 8 by squeezing the handles 2I and 23 between the operatorsiingers.

'Ihe operation of my syringe is as follows.

The syringe when not used has the spring I6 fully extended with theplunger in the cylinder and the casing II moved fully over the cylinderas shown in Fig. 1. For drawing a liquid into the cylinder, the handlesI4 are squeezed together thereby releasing the grip of the clamping ringI5 on the cylinder. The casing is then moved back until its front edgeregisters with a mark on a scale 24 indicating the volume of the liquid'which is desired to introduce into the cylinder. The handles I4 are thenreleased so that the ring I5 clamps the cylinder, retaining the sleevein this position. The spring is then compressed between the front flangeof the sleeve I'i and the clamping ring I5. 'Ihis position of the sleeveis shown in Fig. 2. The needle 4 is then placed in the liquid, and thehandles 2i moved toward the handles 23 thereby releasing the lugs I9from the rim The rear end of the spring becomes now free and it exertsits full pressure on the iiange it of the piston, moving the latter outof the cylinder and thereby sucking the liquid into the cylinder throughthe needle. The syringe can now be left in the liquid and it willcontinue to draw the liquid until the rear end of the plunger comes torest against the cap i2 in the casing. This position is shown in Fig. 3.The spring becomes again fully extended. It has a certain initialtension in this position, however, Which is necessary in order tocontinue drawing the liquid until the last moment when the piston orplunger is stopped by the cap i2.

For injecting the liquid through the needle into living tissues, the'syringe is rst prepared by squeezing together the handles 2i and 23 andmoving the collar or sleeve il forward until the hooks 20 pass beyondthe rim 8 when the handles are released. The hooks 20 engage the rim 8thereby retaining the spring under compression.

The syringe in this charged and cocked position canbe handled and evencarried to the place of operation, the spring remaining locked in thecompressed condition between the clamping ring I5 and the flange 20 ofthe -sleeve II. The needle may be then inserted into tissues forhypodermic injection, the guide lugs 'l limiting the depth of insertion.The syringe is then held steadily in the operators hand while thehandles I4 are squeezed together, releasing the clamping ring. Thespring will then be released for expansion and will move the front endof the casing II toward the front end of the cylinder, forcing theplunger into the cylinder by the pressure from the cap I2. Thisoperation will continue automatically until the plungerl moves to theend of its stroke or until the clamping ring is tightened by releasingthe handles I4. The speed of injection can be controlled by varying thepressure on the handles I4 and using the clamping ring I5 as a. brake.

It may be noted that the hand and the ngers do not move the pistonduring the injection so that the syringe can remain perfectly steady,

the slight variations in the pressure on the handles I4 being too slightto cause any change in the steadiness of the operators hand.

My device can be used as an attachment for an ordinary syringe and canbe easily removed for cleaning and sterilizing the syringe as well asthe attachment. 1

I claim as my invention:

1. For a hypodermic syringe having a. cylinder, a plunger and a needleon the front end of the cylinder, an attachment comprising a helicalspring on the cylinder, means to releasably engage the front end of thespring to the cylinder at a desired point, means` to releasably engagethe rear end of the spring to the rear end of the cylinder therebyrendering the spring inoperative, and means to release the rear end ofthe spring, the rear end of the spring when released being, adapted toengage the rear end of the plunger for withdrawing the latter from thecylinder.

2. For a hypodermic syringe having a cylinder, a plunger and a needle onthe front end of the cylinder, an attachment comprising a helical springonthe cylinder, a tubular casing enclosing the spring, -a clamp in thefront end of the casing adapted to be manually operated :for engagingthe front end of the spring with the casing to the cylinder at a desiredpoint, means to engage the rear end of the spring to ,the rear end ofthe cylinder for rendering the spring inoperative, handles extendingfrom the rear end engaging means, the casing having slots for thehandles, the handles being adapted to be manually operated for releasingthe rear e-nd of the spring, means to transmit the spring pressure tothe rear end of the plunger, and means on the casing to stop themovement of the plunger at the end of the travel determined by thesetting of the front clamping means.

3. For a hypodermic syringe having a cylinder, a piston and a needle, anattachment comprising a helical spring on the cylinder, an enclosingmember on the outside of the spring, a ring at the front end of thespring retained by the end portion of the enclosing member, the ringbeing twisted and made of a resilient material so as to press by thetwisted sides against the sides of the 'cylinder thereby locking thefront end of the spring in a selected position on the cylinder, handlesextending from the twisted sides of the ring and adapted to be manuallymoved for untwisting the ring thereby releasing its pressure on thecylinder, a,sleeve movably supported in the enclosing member andabutting the rear end of the spring, and a ange on the sleeve engagingthe rear end of the plunger thereby transmitting the spring pressure tothe plunger for its withdrawal from the cylinder.

4. A Ihypodermic syringe comprising a cylinder,- a plunger in thecylinder, the cylinder being adapted to support a needle on its frontend, the cylinder having a shoulder on the rear end, the plunger havinga ange on the rear end, a tubular enclosure slidably fitted over thecylinder and spaced therefrom, the front end of the enclosure beingslidably closed over the cylinder, the rear end of the enclosure beingclosed over the rear end of the plunger, a compression helical springsupported in the space between the cylinder and the enclosure, aclamping member at the front end of the enclosure adapted to retain thefront end of the spring in engagement with the cylinder, means tomanually release the clamping means, a sleeve slidably tted in thevenclosure between the rear end of the spring and the plunger ange, andmeans on the sleeve for clamping it to the shoulder on the rear end ofthe cylinder, the spring being adapted through the enclosure to move theplunger into the cylinder when the front clamp is released.

5. A hypodermic syringe comprising a cylinder, a plunger in thecylinder. the cylinder being adapted to support a needle on its frontend, a helical spring slidably tted on the cylinder, a tubular membertted over the spring, the front end of the spring engaging the front endof the tubular member, the rear end of the tubular member abutting therear end of the plunger, a sleeve slidably fitted in the rear portion ofthe tubular member, the front end of the sleeve abutting the rear end ofthe spring, a clamp at the front end of the tubular member adapted tohold the front end of the spring against the cylinder, a. flange on therear end. of the plunger, the sleeve abutting the plunger ange, means tomanually release the clamp for compressing the spring by moving itsfront end with the tubular member to `a desired point on the cylinder,the spring when compressed being adapted to move the plunger through thesleeve out of the cylinder until the rear end of the plunger returns toa, contacting position with the rear end of the tubular member, and amanually releasable means on the sleeve for engaging the rear end of thecylinder thereby compressing the spring after the plunger has been movedout of the cylinder, the spring being then adapted to move the plungerinto the cylinder upon release of the front clamp.

LEONID A. DUNAJEFF.

